Quite often there is need for on site equipment which can be used for lifting heavy articles, for example lifting an engine from a vehicle, but such equipment necessarily occupies a large volume, and for transport purposes needs to be easily demounted or knocked down to a series of components, and readily re-erected. Accordingly, one of the objects of this invention is to provide equipment which can be readily erected, and in particular, when so erected can be very safe so that accident hazard is reduced as far as is reasonably practicable.